Flexible, collapsible containers made of polyvinyl chloride plastic, polypropylene-based materials, etc. are presently in commercial use, particularly for the dispensing of parenteral solutions, blood, and the like. In many designs of such containers, it is desirable to place a stiffening member in the end of the container, to provide support to promote flat collapse as it is hung on an IV pole or the like for administration of blood, parenteral solution, or any other liquid as desired. The stiffener member facilitates the flat collapse of the container by holding the tail end of the container in a linear configuration, and promotes the accurate reading of volume graduations.
At the present time manual and mechanical methods have been proposed for inserting the stiffener member into the tail end of such containers. Manual methods are relatively high in their labor costs, and the mechanical methods involve expensive machinery, and are subject to mechanical breakdown because of their high complexity of the machinery and the criticality required in the placement of stiffener members into bags.
Furthermore, accomodation must be made for the fact that some collapsible bag materials, such as polyvinyl chloride, tend to shrink during the heat sterilization process. Accordingly, the stiffener member must be properly proportioned so that it fits the width of the sterilized container, and not just the container in its as-made configuration.
This invention provides a simplified method for fabricating collapsible containers with an installed stiffener member. The method is highly automated, and provides essentially flawless commercial production capability for large numbers of such flexible collapsible containers at a significantly reduced manufacturing cost over the cost of the previously suggested methods for installing a stiffener member in a flexible, collapsible container.